Photobiological measuring device and analyzing method

Abstract

A photobiological measuring device has a computing unit generating an unwanted component removal observation signal by removing the signal corresponding to the unwanted component from an observation signal. The computing unit is provided with: a mixing matrix making unit for separating observation signals into the products of a mixing matrix and independent component signals through independent component analysis; a power spectrum computing unit generating transformed independent component signals, which are functions of frequency and intensity, by Fourier transforming the independent component signals, which are functions of time and intensity, and computing power spectra in predetermined frequency bands of transformed independent component signals; and an unwanted component signal determining unit detecting the independent component signal corresponding to the unwanted component from among the independent component signals by comparing the power spectrum in a predetermined frequency band of each transformed independent component signal with a threshold.

1 . A photobiological measuring device, comprising:
 a light transmitting/receiving unit having a number of light transmitting probes to be provided on the surface of the skin of a subject and a number of light receiving probes to be provided on the surface of the skin;   a light transmitting/receiving unit control unit acquiring an observation signal indicating chronological variations concerning a portion to be measured in a subject by allowing said light transmitting probes to irradiate the surface of the skin with light while controlling said light receiving probes in order to detect light emitted from the surface of the skin; and   a computing unit generating an unwanted component removal observation signal by removing the signal corresponding to the unwanted component from said observation signal, wherein   said computing unit comprises:   a mixing matrix making unit separating observation signals into the products of a mixing matrix and independent component signals through independent component analysis;   a power spectrum computing unit generating transformed independent component signals, which are functions of frequency and intensity, by Fourier transforming the independent component signals, which are functions of time and intensity, and thus computing power spectra in predetermined frequency bands of the transformed independent component signals; and   an unwanted component signal determining unit detecting the independent component signal corresponding to the unwanted component from among the independent component signals by comparing the power spectrum in a predetermined frequency band of each transformed independent component signal with a threshold,   
     
     
         2 . The photobiological measuring device according to  claim 1 , wherein said computing unit comprises:
 an unwanted component removal mixing matrix making unit making an unwanted component removal mixing matrix in which 0 is substituted for the column vector corresponding to an unwanted component in said mixing matrix on the basis of the independent component signal corresponding to an unwanted component found in said unwanted component signal determining unit; and   an unwanted component removal observation signal generating unit generating unwanted component removal observation signals by multiplying an unwanted component removal mixing matrix with independent component signals.   
     
     
         3 . The photobiological measuring device according to  claim 1 , wherein said predetermined frequency band is at least one frequency band selected from the group consisting of a frequency band indicating the blood flow in the skin, a frequency band indicating fluctuations in the heart rate, and a frequency band indicating pulsation or respiration. 
     
     
         4 . An analysis method for generating an unwanted component removal observation signal by removing the signal corresponding to an unwanted component from an observation signal using a photobiological measuring device comprising:
 a light transmitting/receiving unit having a number of light transmitting probes to be provided on the surface of the skin of a subject and a number of light receiving probes to be provided on the surface of the skin; and   a light transmitting/receiving unit control unit acquiring an observation signal indicating chronological variations concerning a portion to be measured in a subject by allowing said light transmitting probes to irradiate the surface of the skin with light while controlling said light receiving probes in order to detect light emitted from the surface of the skin,   the analysis method being characterized by comprising:   a mixing matrix making step of separating observation signals into the products of a mixing matrix and independent component signals through independent component analysis; and   a unwanted component signal determining step of finding the independent component signal corresponding to an unwanted component from among independent component signals by comparing the power spectrum in a predetermined frequency band in each transformed independent component signal with a threshold.